doesn't /*array.push(forEach loop)*/ work?

const numbers = [1,2,3,4,5,6,7,8,9,10];
let times5 = [];

// again, we need forEach so we can run a function for each item
// to possibly do something with that item. You're not obligated
// to use the item, but generally you do need it like in this case
// where you want to multiple each one by 5
numbers.forEach(num => {
  // this is the function we execute for each num. Let's do it

  // for demonstration purposes we'll multiple by 5 and save
  // that value to a variable
  const numberMultipliedBy5 = num * 5

  // now we need to put our new number in the times5 array with
  // the push method
  times5.push(numberMultipliedBy5)
})

const numbers = [1,2,3,4,5,6,7,8,9,10];
let times5 = [];

numbers.forEach(num => times5.push(num * 5))

const numbers = [1,2,3,4,5,6,7,8,9,10];
let times5 = [];

// I'm saving the return value of executing forEach
// which is undefined. It's important to note that this
// is not the return value of the function passed to forEach
const thisValueisUndefined = numbers.forEach( num => {
  // again this is the function we execute for each num

  // we are indeed multiplying each number by 5 but then we
  // aren't saving it anywhere. forEach is flexible
  // that way but it's your responsibility to save the values
  // somewhere if that's what you want. Returning it doesn't
  // do anything for us.
  return num*5
})

// now we push the return value of running the forEach function,
// NOT the return value from the function passed to forEach. Since
// this value is undefined the times5 array is simply [undefined]
times5.push(thisValueisUndefined);